Stability of renal parenchymal volume and function during active surveillance of renal oncocytoma patients.

INTRODUCTION AND OBJECTIVE: To evaluate whether significant loss in ipsilateral renal parenchymal volume (IRPV) and renal function occurs during active surveillance (AS) of renal oncocytoma (RO) patients. METHODS: Renal function (estimated glomerular filtration rate, eGFR) dynamics were retrospectively analyzed in 32 consecutive biopsy-diagnosed RO patients managed with AS at a National Comprehensive Cancer Network institute. Three-dimensional kidney and tumor reconstructions were generated and IRPV was calculated using volumetry software (Myrian®) for all patients with manually estimated RO growth >+10 cm3. GFR and IRPV were compared at AS initiation vs. the last follow-up using 2-sided paired t-tests. The correlation between change in IRPV and change in RO size or GFR was tested using a Spearman coefficient. RESULTS: With median follow-up of 37 months, there was no significant change between initial vs. last eGFR (median 71.0 vs. 70.5 ml/min/1.73 m2, P = 0.50; median change -3.0 ml/min/1.73 m2). Among patients (n = 17) with RO growth >+10 cm3 during AS (median growth +28.6 cm3, IQR +16.9- + 46.5 cm3), IRPV generally remained stable (median change +0.5%, IQR -1.2%- + 1.2%), with only 2 cases surpassing 5% loss. No IRPV loss was detected among any patient within the top tertile of RO growth magnitude. RO growth magnitude did not correlate with loss of either IRPV (ρ = -0.30, P = 0.24) or eGFR (ρ = -0.16, P = 0.40), including among patient subsets with lower initial eGFR. Study limitations include a lack of long-term follow-up. CONCLUSIONS: Volumetry is a promising novel tool to measure kidney and tumor tissue changes during AS. Our study using volumetry indicates that clinically significant loss of IRPV or eGFR is uncommon and unrelated to tumor growth among untreated RO patients with intermediate follow-up. These findings support that AS is in general functionally safe for RO patients, however longer study is needed to determine safety durability, particularly among uncommon ≥cT2 RO variants.

Active Surveillance for Risk Stratification of All Small Renal Masses Lacking Predefined Clinical Criteria for Intervention.

PURPOSE: Despite general indolence of small renal masses and no known adversity from treatment delays, broad usage of active surveillance as a means to risk-stratify patients with small renal masses for more selective treatment has not been studied. We describe outcomes for a novel approach in which active surveillance was recommended to all patients with small renal masses lacking predefined progression criteria for intervention. MATERIALS AND METHODS: All nondialysis dependent patients with nonmetastatic small renal masses seen by 1 urologist at a comprehensive cancer center during January 2013-September 2017 were managed with active surveillance if standardized progression criteria for intervention were absent, with delayed intervention recommended only upon progression criteria for intervention development. Progression criteria for intervention were defined prospectively as small renal mass-related symptoms, unfavorable histology, cT3a stage or either of the following without benign neoplastic biopsy histology: longest tumor diameter >4 cm; growth rate >5 mm/year for longest tumor diameter ≤3 cm or >3 mm/year for longest tumor diameter >3 cm. RESULTS: In all, 96% (123/128) of patients with small renal masses lacked progression criteria for intervention at presentation and underwent active surveillance. With median/mean 31/34 months followup, none developed metastasis and 30% (37/123) developed progression criteria for intervention, 78% (29/37) of whom underwent delayed intervention. One (1%) patient crossed over to delayed intervention without progression criteria for intervention. Three-year progression criteria for intervention-free and delayed intervention-free rates were 72% and 75%, respectively. Delayed intervention resections were enriched (62%) for pT3 and/or nuclear grade 3-4 malignant pathology, with no benign resections. CONCLUSIONS: Active surveillance using predefined progression criteria for intervention in otherwise unselected patients with small renal masses allows intervention to be focused on at-risk small renal masses with common adverse pathology, avoiding treatment for most patients with small renal masses. Long-term delayed intervention and oncologic safety require study.

Recommendations for acquisition, interpretation and reporting of whole body low dose CT in patients with multiple myeloma and other plasma cell disorders: a report of the IMWG Bone Working Group.

Whole Body Low Dose CT (WBLDCT) has important advantages as a first-line imaging modality for bone disease assessment in patients with plasma cell disorders and has been included in the 2014 International Myeloma Working Group (IMWG) criteria for multiple myeloma (MM) definition. Nevertheless, standardization guidelines for the optimal use of WBLDCT in MM patients are still lacking, preventing its more widespread use, both in daily practice and clinical trials. The aim of this report by the Bone Group of the IMWG is to provide practical recommendations for the acquisition, interpretation and reporting of WBLDCT in patients with multiple myeloma and other plasma cell disorders.

Identification and Validation of Radiographic Enhancement for Reliable Differentiation of CD117(+) Benign Renal Oncocytoma and Chromophobe Renal Cell Carcinoma.

Purpose: The diagnostic differential for CD117/KIT(+) oncocytic renal tumor biopsies is limited to benign renal oncocytoma versus chromophobe renal cell carcinoma (ChRCC); however, further differentiation is often challenging and requires surgical resection. We investigated clinical variables that might improve preoperative differentiation of CD117(+) renal oncocytoma versus ChRCC to avoid the need for benign tumor resection.Experimental Design: A total of 124 nephrectomy patients from a single institute with 133 renal oncocytoma or ChRCC tumors were studied. Patients from 2003 to 2012 comprised a retrospective cohort to identify clinical/radiographic variables associated with renal oncocytoma versus ChRCC. Prospective validation was performed among consecutive renal oncocytoma/ChRCC tumors resected from 2013 to 2017.Results: Tumor size and younger age were associated with ChRCC, and multifocality with renal oncocytoma; however, the most reliable variable for ChRCC versus renal oncocytoma differentiation was the tumor:cortex peak early-phase enhancement ratio (PEER) using multiphase CT. Among 54 PEER-evaluable tumors in the retrospective cohort [19 CD117(+), 13 CD117(-), 22 CD117-untested], PEER classified each correctly as renal oncocytoma (PEER >0.50) or ChRCC (PEER ≤0.50), except for four misclassified CD117(-) ChRCC variants. Prospective study of PEER confirmed 100% accuracy of renal oncocytoma/ChRCC classification among 22/22 additional CD117(+) tumors. Prospective interobserver reproducibility was excellent for PEER scoring (intraclass correlation coefficient, ICC = 0.97) and perfect for renal oncocytoma/ChRCC assignment (ICC = 1.0).Conclusions: In the largest clinical comparison of renal oncocytoma versus ChRCC to our knowledge, we identified and prospectively validated a reproducible radiographic measure that differentiates CD117(+) renal oncocytoma from ChRCC with potentially 100% accuracy. PEER may allow reliable biopsy-based diagnosis of CD117(+) renal oncocytoma, avoiding the need for diagnostic nephrectomy. Clin Cancer Res; 24(16); 3898-907. ©2018 AACR.